Admitting the existence of the soul, we know of no force which is able to put an end to her.

Vice is her own proper evil; and if she cannot be destroyed by that, she cannot be destroyed by any other.
Yet Plato has acknowledged that the soul may be so overgrown by the incrustations of earth as to lose her original form; and in the Timaeus he recognizes more strongly than in the Republic the influence which the body has over the mind, denying even the voluntariness of human actions, on the ground that they proceed from physical states (Tim.).

In the Republic, as elsewhere, he wavers between the original soul which has to be restored, and the character which is developed by training and education...
The vision of another world is ascribed to Er, the son of Armenius, who is said by Clement of Alexandria to have been Zoroaster.

The tale has certainly an oriental character, and may be compared with the pilgrimages of the soul in the Zend Avesta (Haug, Avesta).

But no trace of acquaintance with Zoroaster is found elsewhere in Plato's writings, and there is no reason for giving him the name of Er the Pamphylian.